Plastic blow molded containers conventionally include a body portion for holding liquid contents such as detergent and also have an upper open end through which the liquid contents can be dispensed. Prior to the last ten years or so, such containers conventionally included threads or other suitable retainers on the upper open end for securing a closure cap that is removable to permit the dispensing and thereafter secured by the retainers. Such closure caps cannot be easily utilized to provide measuring of the required amount of liquid contents since the liquid remaining in the closure cap will drip onto the container exterior upon subsequent securement by the retainers so that the container is disadvantageously messy.
More recently, drain-back closure assemblies have been developed to allow measuring with a cup-like closure that is secured to a plastic blow molded container by a drain-back member mounted on the upper open end of the container. Such drain-back closure assemblies allow the liquid remaining within the cup-like closure to drain back into the container after securement thereof to the drain-back member without dripping liquid onto the exterior of the container. Prior art patents which disclose such drain-back closures include U.S. Pat. Nos. 4,349,056 Heino; 4,550,862 Barker et al; 4,640,855 St. Clair; and 4,981,239 Coppel et al.